The present invention relates to an injection syringe, particularly for medical purposes, for injecting high viscosity pastes and whose actuating parts constructed in the form of gripping handles with notches engage in a piston rod provided with corresponding step-like parts and which can be advanced stepwise into the syringe cylinder together with the syringe piston.
The known injection syringes of this type are constructed inter alia with a long injection cannula, which is slightly elastic and can be introduced into a corresponding channel of an endoscope. The syringe cylinder must remain outside the endoscope, because not only is it rigid, but also has a larger diameter than the endoscope channel, e.g. 12 mm.
In the field of medicine, generally liquids are injected. The higher the viscosity of the liquids to be injected the higher must be the pressure in order to force the liquid through the thin injection cannula. For injecting highly viscous substances, e.g. pastes, syringes of the type indicated hereinbefore are known, whose piston rod is constructed in the manner of a rack. By a corresponding transmission ratio of the actuating parts the rack can be advanced in stepwise manner with a much larger force than in conventional syringes. However, the diameter is so large that, despite the relatively high force, the paste generally remains stuck in the long cannula.